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Full text of "The Morphology And Evolution Of The Apes And Man"

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TABSIOIDEA                               31
present.    The facial and auricular muscles, particularly the latter, are well marked.
The sterno-mastoid has no clavicular head of origin, and the trapezius merely reaches the occipital bone. The lower part of the trapezius forms a muscle known as the depressor scapulae. A strip of muscle termed the occipito-scapularis is present beneath the trapezius. The pre-tracheal and most of the submental muscles are not peculiar, but the digastric muscle has two bellies in contradistinction to the monogastric form in the Lemurs. In Man the muscle has two separate bellies.
The pectoral muscles are much as in the Lemurs, but the deltoid muscle is not so extensive; it is divided into two parts as in some Marsupials. The latissimus dorsi gives off the dorso-epitrochlearis, but the latter arises from the muscle itself; in its origin the latter differs from that of the Lemurs.
The muscles of the arm, forearm and matins are much as in the Lemurs, but Duckworth (50) points out that the flexor longus pollicis is almost independent of the flexor profundus digitorum, though still receiving a slip from the flexor sublimis. In the separation of the flexor longus pollicis Tarsius resembles the higher Primates.
The lower limit of the insertion of the glutens maximus is in the lower part of the thigh, a condition which resembles that in the Chimpanzee. The biceps has no femoral head, but the examination of many animals might show that this is variable as in the higher Apes.
The -vastus externus is large as in the Lemurs, and the tibialis anticus is likewise greatly developed; but the tibialis posticits arises from both tibia and fibula. The soleus arises from the fibula alone as in the Lemurs and